1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Speed of a boat due to power rower

  1. Jun 24, 2013 #1
    1. The problem statement, all variables and given/known data
    Dear all, I need help with an old exam question. It goes as following:

    The maximum power that a certain athlete can produce is equal to 1 kW. What is the theoretical maximum speed that a rower can obtain in a rowboat with a smooth exterior, a length of 4 meter and a 'wet' surface of 2.8 m^2.

    2. Relevant equations
    No equations are given and I can't think of any. However, the density of air (1.2 kg/m^3), the dynamic viscosity of air (1.8*10^-5 Pa s), the density of water (1000 kg/m^3), the dynamic viscosity of air (0.0010 Pa s) are all given, though it does not say which (if any) I should use.

    3. The attempt at a solution

    I have been attempting to recreate a formula based on the units of the various components. One formula for power = force * speed, so speed=Power/force. For force, which is in newton, I tried multiplying the viscosity of the water with the 'wet' area. The resulting number would have newton as its unit (Pa*s*m^2 is equal to kg*m/s=Newton). However, this left me with a speed in the 6 digits, which I don't think is a realistic answer for a row boat.
    I have tried other combinations as well, but these don't result in the right unit (m/s). Please help.
  2. jcsd
  3. Jun 25, 2013 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted